The present invention refers to a device for stretching and fixing a cloth such as a screen-, strainer-, bolting-, filter cloth or similar material on a frame of the kind comprising a frame-shaped stand, a pressure plate movable in the border of the stand and extending over an essential part of said border and at least one member acting upon the pressure plate for displacing the pressure plate towards the cloth.
When mounting cloths of the above mentioned kind it is important that the cloth is stretched regularly over the whole surface area. For small frames the stretching and fixing have been made manually and inevitable irregularities following such a manual operation had to be tolerated. For large frames including several square meters pneumatic frame stretching devices have been used, which by means of a great number of pneumatic stretching means stretches the cloth until the sufficient stretching force is obtained. With these machines a good result is obtained, but the fixing of a great number of stretching means is difficult and very time-requiring. Moreover such machines are very expensive and require a large space. An example of such a device is described in the Swiss patent specification No. 402.790.
In the German Auslegeschrift No. 2.020.958 is described a device of the kind mentioned above, which however has certain drawbacks. Thus the pressure plate can be displaced only perpendicular to the guides in the frame. By reason of that the pressure plate cannot compensate possible irregularities of the stretching of the cloth against the frame.
In the U.S. Pat. No. 1,778,385 a device for stretching a skin against a stencil is described, at which pneumatic pads are used. The purpose is to make the stencil lie tightly against the skin, thus preventing the dye or other colouring material used from running underneath the stencil. This device is accordingly intended for a quite different purpose and for a different technical field than the device according to the invention.